1. Field of the Invention
The invention relates to a method for detecting a double-talk condition, in particular, to a method for detecting a double-talk condition by comparing powers within a linear region of estimated signals.
2. Description of Related Art
Techniques about echo cancellation are widely implemented in communication devices such as telephones. With the functionalities of echo cancellation, the user of the communication devices may normally perform voice input operations without being interfered by the echoed signals from the speaker of the communication devices.
In the field of echo cancellation techniques, it is important to detect whether a double-talk (DT) condition occurs during the procedure of echo cancellation. Without the detection of the double-talk condition, the performance of the echo cancellation would be dramatically deteriorated since the estimated echo channel may be different from the real echo channel. In detail, when the double-talk condition occurs, the echo signal would be mixed into a near-end signal that can be strongly correlated to the far-end, resulting in large interference components in the error signal. As a result, the echo canceller would diverge from its converged state if the adaptive filter updates its filter coefficients during the DT periods. Therefore, it is important to distinguish the states of the microphone input among the near-end only, the far-end only, and the DT periods.
Usually, the conventional double-talk detector (DTD) detects whether the double-talk condition occurs by taking gradient to the estimated echo channel for exploiting the energy level change. However, the computational complexity of the gradient operation is high. Besides, when the estimated echo channel is not accurate, the result of the double-talk condition detection would be erroneous as well.